1. Field Of The Invention
This invention relates to an improved waterproofing laminate and, more specifically, it relates to such laminates which are particularly useful in connection with waterproofing of building surfaces such as roofs, floors and other surfaces wherein it is desired to resist penetration of water or water vapor.
2. Description Of The Prior Art
It has been known to employ in various roofing systems built-up roofing. Such systems may include a layer of bituminous roofing felt, a bitumen layer coated on one or both surfaces of the felt and a material such as gravel, sand or the like which is deposited on an exposed bitumen layer. Among the problems found in such systems is that they require extensive field labor, tend to lack uniformity in respect of structural nature and effectiveness from zone to zone and may not perform effectively under a wide variety of climatic conditions.
It has also been known to employ waterproof sheeting which has been applied to a substrate such as a roof substrate using molten bitumen or cold applied bituminous adhesives. Among the problems with such approaches is the failure of the elastomeric sheeting to maintain dimensional stability and avoid wrinkling when bonded with hot bitumen. Also, depending upon the conditions at the time of application the adhesive bond can vary in effectiveness substantially. On slopes greater than about 10 degrees it is generally necessary to employ mechanical fasteners to secure the membrane in place. Such membranes must generally be left exposed for periods in excess of about 30 days before painting in order to permit the adhesive to cure completely. Such adhesively securd elastomeric sheetings also can generally not be applied directly to insulation, wood, metal, concrete and other materials. Also, in warm weather the temperature of the roof can reach such a level that the adhesive liquifies.
It has been known to provide laminated roofing membranes which contain bitumen coated layers and compound bitumen coated layers. See U.S. Pat. Nos. 4,055,453 and 4,091,135 the disclosures of which are expressly incorporated herein by reference.
It has been known that elastomeric materials such as natural or synthetic rubber and bituminous materials tend to be incompatible and that bituminous materials will tend to attack and degrade elastomeric materials.
There remains, therefore, a very real and substantial need for a waterproofing laminate which will provide effective, dependable waterproofing to a roof, floor, below grade installation or other installaton making waterproofing characteristics desirable or necessary.